System and method for predicting soot content in diesel engines

ABSTRACT

A method for predicting soot content in diesel engines includes generating a look-up table of the rates of soot introduction into the engine oil based on one or more engine operating conditions. A control module monitors the engine operating condition and determines the soot content in the oil based thereon. When the soot content exceeds a predetermined critical soot content value, the control module sends a signal to an output device to indicate that the engine oil must be changed to avoid damage to the engine.

TECHNICAL FIELD

[0001] The present invention relates generally to diesel engines.

BACKGROUND OF THE INVENTION

[0002] Typically, in diesel engines, the combustion process yields much more soot than gasoline engines. As such, there is a greater likelihood that soot will be introduced into the engine oil, e.g., by combustion gases leaking around the piston rings. Consequently, diesel engines are more likely to be damaged by soot than conventional gasoline engines.

[0003] In contrast to conventional gasoline engines, the rate of degradation of oil used to lubricate diesel engines is often determined by the rate at which soot is introduced into the diesel engine oil. Accordingly, the interval at which the diesel engine oil must be changed is often dependent on the amount of soot in the oil. When the soot in the engine oil reaches a critical level, the oil must be replaced with fresh soot-free oil.

[0004] The present invention recognizes that there currently is not a sensor that can relatively easily and relatively reliably be used to measure the soot content in the diesel engine oil. In lieu of a sensor, sampling methods have been used whereby oil is taken from a diesel engine and processed in a laboratory to determine the soot content. These sampling methods take time and are costly.

[0005] The present invention has recognized these prior art drawbacks, and has provided the below-disclosed solutions to one or more of the prior art deficiencies.

SUMMARY OF THE INVENTION

[0006] A method for predicting soot content in engine oil includes monitoring an engine operating condition and determining the soot introduction rate based thereon.

[0007] In turn, the soot content can be determined based on the soot introduction rate. Preferably, a look-up table of soot introduction rates based on the engine operating condition is generated. The look-up table is accessed using the engine operating condition as an entering argument and the soot introduction rate is determined based on the engine operating condition. The soot introduction rate is then used to determine the soot content in the engine oil. In a preferred embodiment, when the soot content exceeds a critical soot content value, it is indicated that the engine oil must be changed. Preferably, the look-up table is generated for at least one class of engine. Moreover, in a preferred embodiment, the engine operating condition is an engine operating temperature, an engine operating load, an engine operating speed, an elapsed engine operating time, a mileage value, fuel composition, fuel consumption rate, and/or an exhaust gas recirculation rate.

[0008] In another aspect of the present invention, a method for predicting soot content in an engine includes generating at least one look-up table of soot introduction rates based on an engine operating condition and monitoring the engine operating condition. In this aspect, the look-up table is accessed using the engine operating condition as an entering argument in order to determine the soot content in the engine oil.

[0009] In yet another aspect of the present invention, a system for predicting soot content in engine oil includes an engine and an oil pan that provides oil to the engine. A control module monitors an engine operating condition and includes a program for predicting the soot content in the engine oil based on the engine operating condition.

[0010] In still another aspect of the present invention, a system for predicting soot content in engine oil includes an engine and an oil pan that provides oil to the engine. An oil sensor monitors an engine operating condition and includes a program for predicting the soot content in the engine oil based on the engine operating condition.

[0011] The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a block diagram of a diesel engine lubricating system;

[0013]FIG. 2 is a flow chart of the present calibration logic; and

[0014]FIG. 3 is a flow chart of the present operation logic.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

[0015] Referring initially to FIG. 1, a diesel engine oil lubricating system is shown and generally designated 10. FIG. 1 shows that the system 10 includes a diesel engine 12 in fluid communication with an oil pan 14 to provide lubricating oil to the internal engine components, e.g., the crankshaft, camshafts, rocker arms, pushrods, pistons, etc. FIG. 1 further shows a control module 16 electrically connected to the engine 12 by electric line 18. Also, an output device 20 is electrically connected to the control module 16 by electric line 22. An oil sensor 24 is disposed in the oil pan 14 such that it communicates with oil therein. The sensor 24 is electrically connected to the control module 16 by electric line 26 and can receive data concerning engine operating parameters therefrom.

[0016] It is to be understood that the control module 16 can be, e.g., an engine control module (ECM) or a body control module (BCM). Moreover, it is to be understood that the output device 20 can be an audible warning device, e.g., a buzzer or audible alarm. The output device 20 can also be a visual warning device, e.g., a warning lamp or other visual display. Or, the output device 20 can be a visual indicator of the soot content in the engine oil, e.g., a gauge or similar device.

[0017] While the preferred implementation of the control module 16 is an onboard chip such as a digital signal processor, it is to be understood that the logic disclosed below can be executed by other digital processors, such as by a personal computer. Or, the control module 16 may be any computer, including a Unix computer, or OS/2 server, or Windows NT server, or a laptop computer.

[0018] The control module 16 includes a series of computer-executable instructions, as described below, which will allow the control module 16 to predict the soot content in the engine oil based on one or more engine operating conditions. These instructions may reside, for example, in RAM of the control module 16. On the other hand, in the case of a “smart” sensor, the instructions reside in RAM of the oil sensor 24.

[0019] Alternatively, the instructions may be contained on a data storage device with a computer readable medium, such as a computer diskette. Or, the instructions may be stored on a magnetic tape, conventional hard disk drive, electronic read-only memory, optical storage device, or other appropriate data storage device. In an illustrative embodiment of the invention, the computer-executable instructions may be lines of compiled C++ compatible code.

[0020] The flow charts herein illustrate the structure of the logic of the present invention as embodied in computer program software. Those skilled in the art will appreciate that the flow charts illustrate the structures of computer program code elements including logic circuits on an integrated circuit, that function according to this invention. Manifestly, the invention is practiced in its essential embodiment by a machine component that renders the program elements in a form that instructs a digital processing apparatus (that is, a computer) to perform a sequence of function steps corresponding to those shown.

[0021] Referring to FIG. 2, an exemplary, non-limiting embodiment of the calibration logic of the present invention is shown. Commencing at block 30, a do loop is entered wherein for each engine class, i.e., for each different sizes and engine configurations, the succeeding steps are performed. Thereafter, at block 32 a second do loop is entered wherein for a range of engine operating parameters, the following steps are performed. It is to be understood that the engine operating parameters include, but are not limited to, the following: engine operating temperature, engine operating load, engine operating speed, elapsed engine operating time, mileage, fuel composition, fuel consumption rate, and/or exhaust gas recirculation rate.

[0022] Proceeding to block 38, the engine is allowed to operate for a predetermined time. Thereafter, at block 40, the engine is stopped. Moving to block 42, the soot introduced into the oil pan, and thus, the engine oil, by the combustion of diesel fuel within the diesel engine is measured. Continuing to decision diamond 44, it is determined whether more data is needed to construct a table of data, described below. If more data is indeed needed, the logic returns to block 38 wherein the engine is again allowed to operate for a predetermined time. The logic then continues to as described above.

[0023] If, at decision diamond 44, more data is not needed, the logic moves to block 46 to complete the above process for all nested loops. When the entire loop ranges have been executed, the logic moves to block 48 where look-up table for soot introduction versus engine operating time are generated for each engine class over the ranges of engine parameters used above. Then, at block 50, the look-up tables for the relevant engine class are downloaded to the control module 16.

[0024] It is to be understood that numerous look-up tables can be generated to simulate the operating conditions for different classes of engines. Diesel engines used in tractor trailers will have greater loads put on them than, e.g., stationary diesel power generators. Moreover, the look-up tables are preferably generated for soot introduction versus engine operating time rather than mileage because many diesel engines are used in low mileage, or no mileage, applications, e.g., stationary power generators, excavators, front-end loaders, etc. However, it can be appreciated that for tractor trailers and other high mileage vehicles having diesel engines, look-up tables can be generated for soot introduction versus mileage for the ranges of engine operating conditions used above.

[0025] Referring now to FIG. 3, the operation logic of the present invention is shown. Commencing at block 60, a do loop is entered wherein for a diesel engine, the following steps are performed. At block 62, the engine operating conditions are monitored. It is to be understood that the engine operating conditions include, but are not limited to, the following: engine operating temperature, engine operating load, engine operating speed, elapsed engine operating time, mileage, fuel composition, fuel consumption rate, and/or exhaust gas recirculation rate. Moving to block 64, the lockup tables stored in the control module 16 are periodically accessed to determine the soot introduced rates based on the engine operating conditions monitored above. Then, at block 66, the soot content in the engine is determined based on the different soot introduction rates determine above. If desired, a visual indication of the amount of soot introduced into the oil since the previous oil change can be provided to the driver or operator of the diesel engine.

[0026] Continuing to decision diamond 68, it is determined whether oil has been added to the system. If so, the logic moves to block 70 where the soot content value is adjusted to account for the additional oil in the system. Next, the logic proceeds to decision diamond 72 where it is determined whether soot content in the oil is greater than a predetermined critical soot content value. It can be appreciated that the critical soot content value represents a quantity of soot in the engine oil that can be harmful to the engine. If the actual soot content is greater than the critical soot content value, the logic proceeds to block 74 where it is indicated to the driver or operator using, e.g., the output device 22, that it is time to change the oil in the diesel engine 12. If, at decision diamond 72, the soot content is less than the critical soot content value, the logic returns to block 62 where the control module continues to monitor the-engine operating conditions. Then, the logic continues as described above. Returning to decision diamond 68, if oil is not added to the system, the logic moves to decision diamond 72 and proceeds as described above.

[0027] With the configuration of structure and logic described above, it is to be appreciated that the system and method for predicting soot content in diesel engines provides a means for accurately predicting the soot introduced into diesel engine oil from the combustion of diesel fuel therein. Moreover, the system and method for predicting soot content in diesel engines provides a means for accurately determining when the diesel engine oil must be changed based on the rate of soot introduction. It is to be understood that the above logic can be used to predict the soot content in other engines that may fall prey to high soot content in the lubricating oil, e.g., engines that utilize internal injection processes.

[0028] While the particular SYSTEM AND METHOD FOR PREDICTING SOOT CONTENT IN DIESEL ENGINES as herein shown and described in detail is fully capable of attaining the above-described objects of the invention, it is to be understood that it is the presently preferred embodiment of the present invention and thus, is representative of the subject matter which is broadly contemplated by the present invention, that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural and functional equivalents to the elements of the above-described preferred embodiment that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it is to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. section 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.” 

1. A method for predicting soot content in engine oil, comprising the acts of: monitoring at least one engine operating condition; and determining soot introduction rates at least partially based thereon.
 2. The method of claim 1, further comprising the act of: determining soot content at least partially based on the soot introduction rates.
 3. The method of claim 1, further comprising the acts of: generating at least one look-up table of soot introduction rates based on the engine operating condition; and accessing the look-up table using the engine operating condition as an entering argument; and determining soot introduction rates based thereon.
 4. The method of claim 2, further comprising the act of: indicating that engine oil must be changed when the soot content exceeds a critical soot content value.
 5. The method of claim 3, wherein the look-up table is generated for at least one class of engine.
 6. The method of claim 1, wherein the engine operating condition is at least one of: engine operating temperature, engine operating load, engine operating speed, elapsed engine operating time, mileage, fuel consumption rate, fuel composition, and exhaust gas recirculation rate.
 7. The method of claim 2, further comprising the act of: adjusting the soot content at least partially based on fresh oil being added to the engine oil.
 8. A method for predicting soot content in an engine lubricating system, comprising the acts of: generating at least one look-up table of soot introduction rates based on an engine operating condition; monitoring the engine operating condition; accessing the look-up table using the engine operating condition as an entering argument; and determining soot introduction rates at least partially based thereon.
 9. The method of claim 8, further comprising the act of: determining soot content at least partially based on the soot introduction rates.
 10. The method of claim 9, further comprising the act of: indicating that engine oil must be changed when the soot content exceeds a critical soot content value.
 11. The method of claim 9, wherein the look-up table is generated for at least one class of engine.
 12. The method of claim 8, wherein the engine operating condition is at least one of: engine operating temperature, engine operating load, engine operating speed, elapsed engine operating time, mileage, fuel consumption rate, fuel composition, and exhaust gas recirculation rate.
 13. The method of claim 9, further comprising the act of: adjusting a soot content value in response to fresh oil being added to the system.
 14. A system for predicting soot content in engine oil, comprising: at least one engine; at least one oil pan providing oil to the engine; and at least one control module monitoring at least one engine operating condition, the control module including a program for predicting the soot content in the engine oil based at least one engine operating condition.
 15. The system of claim 14, wherein the control module further comprises: at least one look-up table stored therein, the look-up table including soot introduction rates based on the engine operating condition; logic means for accessing the look-up table using the engine operating condition as an entering argument; and logic means for determining a soot content introduction rates based thereon.
 16. The system of claim 15, wherein the control module further comprises: logic means for determining soot content at least partially based on the soot introduction rates.
 17. The system of claim 16, further comprising an output device, the control module further comprises: logic means for sending a signal to the output device when the soot content value exceeds a predetermined critical soot content value.
 18. The system of claim 15, wherein the look-up table is generated for at least one class of engine.
 19. The system of claim 14, wherein the engine operating condition is at least one of: engine operating temperature, engine operating load, engine operating speed, elapsed engine operating time, mileage, fuel consumption rate, fuel composition, and exhaust gas recirculation rate.
 20. The system of claim 16, wherein the control module further comprises: logic means for adjusting the soot content at least partially based on fresh oil being added to the engine oil.
 21. A system for predicting soot content in engine oil, comprising: at least one engine; at least one oil pan providing oil to the engine; and at least one oil sensor monitoring at least one engine operating condition, the oil sensor including a program for predicting the soot content in the engine oil based on at least one engine operating condition.
 22. The system of claim 21, wherein the oil sensor further comprises: at least one look-up table stored therein, the look-up table including soot introduction rates based on the engine operating condition; logic means for accessing the look-up table using the engine operating condition as an entering argument; and logic means for determining soot content introduction rates based thereon.
 23. The system of claim 22, wherein the oil sensor further comprises: logic means for determining soot content at least partially based on the soot introduction rates.
 24. The system of claim 23, further comprising an output device, the oil sensor further comprises: logic means for sending a signal to the output device when the soot content value exceeds a predetermined critical soot content value.
 25. The system of claim 24, wherein the look-up table is generated for at least one class of engine.
 26. The system of claim 21, wherein the engine operating condition is at least one of: engine operating temperature, engine operating load, engine operating speed, elapsed engine operating time, mileage, fuel consumption rate, fuel composition, and exhaust gas recirculation rate.
 27. The system of claim 23, wherein the oil sensor further comprises: logic means for adjusting the soot content at least partially based on fresh oil being added to the engine oil. 